Remove "side" attribute from "textPath"

[karlcow]

It was decided to add it on February 2015 to SVG2
https://www.w3.org/2015/02/12-svg-minutes.html#item05

And it has been defined in
https://w3c.github.io/svgwg/svg2-draft/text.html#TextPathElementSideAttribute

The SVGTextPathElement IDL is not fully defined and does not have the side attribute. It has been acknowledged on issue 391.

This is not implemented in any browsers.
https://wpt.fyi/results/svg/text/reftests/textpath-side-001.svg?label=master&label=experimental&aligned&q=safari%3Afail%20firefox%3Afail%20chrome%3Afail

It should be removed.

[yisibl]

In fact, Firefox has supported the <textPath side> attribute since version 61.

• There is a work-in-progress patch in Chrome, and implementing it doesn't seem particularly difficult.
• I had originally planned to implement this feature for resvg as well.

[karlcow]

@yisibl Is there a test which renders anything?

[yisibl]

http://wpt.live/svg/text/reftests/textpath-side-001.svg
Firefox:

[karlcow]

We need more test cases for this.

[karlcow]

ok the failure in Firefox is related to fuziness. Probably this test should be rewritten to avoid this.